Conventionally, there has been known a mobile communication system in which a plurality of radio base stations receive, in cooperation with one another, uplink signals transmitted from a radio terminal. In such a mobile communication system, selective synthesis of the uplink signals received in the plurality of radio base stations is performed.
For example, in LTE (Long Term Evolution), the uplink signal is transmitted through PUSCH (Physical Uplink Shared Channel).
Here, the plurality of radio base stations include one anchor radio base station and remaining non-anchor radio base stations. The non-anchor radio base stations transmit uplink signals before decoding to the anchor radio base station through a backhaul network. The anchor radio base station performs selective synthesis of uplink signals before decoding, which are transmitted from the radio terminal, and uplink signals before decoding, which are received from the non-anchor radio base stations.
However, in such a case, since the uplink signals before decoding are transmitted from the non-anchor radio base stations to the anchor radio base station through the backhaul network, a load of the backhaul network is increased.